And I'm Robert Siegel. The U.S. and the European Union hit Russia with more sanctions today on both individuals and companies for refusing to deescalate tensions in Ukraine. In a moment, we'll hear more details about those sanctions from NPR's Scott Horsley, but first to eastern Ukraine where the new penalties did little to curb violence.

Pro-Ukrainian protesters who attempted to march through the city of Donetsk came under heavy attack today.

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SIEGEL: NPR's Soraya Sarhaddi Nelson was at that march and she joins us from Donetsk. Soraya, tell us about that protest.

SORAYA SARHADDI NELSON, BYLINE: Well, the march was a very rare one. Pro-Ukrainian groups here are very afraid to come out because the separatists are so great in number and they're quite violent. So this one was organized by a group called Donbas is Ukraine, which refers the name of the eastern Ukrainian region here, in which the city is located.

Many more groups were supposed to attend and supposed to join this march, but they were afraid and postponed. So after about an hour of waiting, there were about a couple hundred people. They were singing the national anthem. They were passing out Ukrainian flags. And they started to march down the main street and they purposefully chose to avoid the occupied government building to avoid confrontation with the separatists.

You had some young male protesters at the front. They were carrying flares. They were a little more aggressive and they started to have basically a verbal fight, if you will, with hecklers that were running alongside. You have to picture riot police on either side of the marchers and then on the other side of that, you had hecklers.

And so that went on for a little while and then suddenly, you could hear flares being thrown, stun grenades, you know, just lots of loud explosive noises. And people started to run and scream in all directions. It was quite chaotic and 15 people were hospitalized for injuries and one cameraman was also attacked with a knife. Separatists also attached five cars that had Ukrainian flags on them and they were traveling in a convoy and honking their horns and so there was damage and, you know, basically the occupants were being harassed there.

SIEGEL: Yes, we heard the sounds earlier, the concussion grenades and the teargas canisters being lobbed. Is it clear who was doing the firing at that point?

NELSON: No. It's not clear, unfortunately, who was firing the concussion grenades and flares and other explosive materials, but there were hundreds of riot police on hand. Some of them on horseback and with dogs and they were supposedly there to keep the peace. But they didn't appear to get involved when the chaos broke out and certainly the pro-Ukrainian marchers were accusing them of just standing aside and letting this violence happen.

And some of the officers, we noticed, were also wearing St. George's ribbons, which suggests that they're pro-Russian. And we saw one guy in civilian clothes who was pointing a gun. And then there were also really menacing-looking guys who were clearly pro-Russian separatists and they were chasing the marchers. There were dozens of them.

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NELSON: These separatists were marching in a tight pack and they were banking on metal shields they were holding.

SIEGEL: Soraya, that was in Donetsk today. I gather there was other violence in eastern Ukraine. Is it true that the mayor of the country's second largest city was shot?

NELSON: Yes. The mayor of Kharkiv, his name is Hennady Kernes, and he was shot in the back as he was riding his bicycle near a forested area near the town. It's unclear who shot him at this stage, but this mayor is someone who had a lot of enemies on both sides. He was very vehemently against the protesters in Kiev and the government that replaced former President Yanukovych, but he also wants a united Ukraine. He doesn't support the separatists. And his aides are reporting that he's in grave but stable condition after undergoing surgery early today.